Four eyes
| Four eyes | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Four-eye ( Anableps anableps ) |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Anableps | ||||||||||||
| Scopoli , 1777 |
The four- eyes ( Anableps ) are a genus of approx. 30 cm long viviparous toothcarps that are common in the muddy coastal waters of northern South America ( Venezuela and Trinidad to the mouth of the Amazon ) and on the Pacific coast of Central America .
Anatomy of the eye
Four- eyes are surface fish with a transverse septum dividing the eye into two halves, each with a pupil, so that the animals can see above and below the water at the same time. The upper half of the lens is weak, the lower half strongly curved to ensure the correct refraction of the light. It is the only known vertebrate (besides one species of frog) that can see clearly both above and below water. In order to be able to see both above and below the water, there are over ten species of opsin in the retina of this fish's eyes (compared to only four in humans).
species
Care in the aquarium hobby
The four-eye in the brackish water aquarium is maintained by some specialized aquarists . If possible, keep them in a basin with a low water level and a well-closing cover so that there is high humidity above the water surface. In the warm aquarium, the surface fish needs a beach area where the fish can rest and an open swimming area. They are kept in groups of six to eight animals so that pairs can form.
More pictures
Individual evidence
- ↑ GL Owens, DJ Windsor, J. Mui, JS Taylor: A Fish Eye Out of Water: Ten Visual Opsins in the Four-Eyed Fish, Anableps anableps. In: PLoS ONE. Volume 4, No. 6, 2009, p. E5970. doi: 10.1371 / journal.pone.0005970
Web links
- Four eyes on Fishbase.org (English)